JP5332130B2 - Fuel cell stack structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell stack structure capable of shortening a starting time and achieving compactness while improving the utilization efficiency of a reforming temperature and the uniformity of the whole temperature distribution. <P>SOLUTION: The fuel cell stack structure is constituted by laminating at a center a plurality of solid electrolyte fuel cell units 1 which have circular cell plates 2 that hold unit cells and have gas inlet holes 21 and gas exhaust holes 22 at the center, a circular separator plate 3 that has a gas inlet hole 31 and a gas exhaust hole 32 at the center and is jointed to the cell plate 2, and a center passage component 5 which is located between each center of both plates 2, 3 and carries out the supply and discharge of a fuel gas in the space through a gas inlet passage 51 communicating with the gas inlet holes 21, 31 and a gas exhaust passage 52 communicating with the gas exhaust holes 22, 32. The space between the adjoining solid electrolyte fuel cell units 1 is made to be an air passage and a porous body 20 is installed in the gas inlet passage 51A which is formed by the continuation of each gas inlet passage 51 of the center passage component 5. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

    The present invention relates to a fuel cell stack structure formed by stacking a plurality of solid oxide fuel cells.

  When the fuel cell stack structure as described above is mounted on an automobile, it is required to have a short start-up time and a small size.

  Conventionally, as a fuel cell stack structure configured to meet these requirements, for example, a plurality of stacked cells and gas between the cells positioned along the stacking direction of these cells and outside the cells are used. Some gas flow paths are provided, and a catalyst is provided in the gas flow path to change the density in the stacking direction (see Patent Document 1).

Further, as a fuel cell stack structure different from this fuel cell stack structure, for example, a plurality of separators and cells having gas flow paths therein are alternately stacked, and a reforming catalyst is provided in the gas flow paths. Some have a configuration in which a supported porous body is disposed (see Patent Document 2).
Japanese Patent Laid-Open No. 5-129032 JP 2004-227849 A

  In the fuel cell stack structure described above, in the former fuel cell stack structure, the density of the catalyst provided in the gas flow path is changed in the stacking direction, so that the flow rate of the fuel gas can be made uniform. Although the fuel gas can be satisfactorily reformed, there is a problem that the utilization efficiency of reforming heat is poor because the gas flow path along the stacking direction is installed outside the cell.

  On the other hand, in the case of the latter fuel cell stack structure, since the porous body carrying the reforming catalyst is disposed in the gas flow path of the separator, if the degree of catalyst deterioration differs for each stage, The components of the gas to be supplied will be different for each stage, and as a result, there is a problem that non-uniformity of the entire temperature occurs, and it has been a conventional problem to solve these problems .

  The present invention has been made by paying attention to the above-mentioned conventional problems, and it is possible to reduce the start-up time and make it compact while improving the utilization efficiency of reforming heat and making the entire temperature distribution uniform. It aims at providing the fuel cell stack structure which is.

  A fuel cell stack structure according to the present invention includes a cell plate that holds a single cell and has a circular shape having a gas introduction hole and a gas discharge hole in the center portion, and a gas introduction hole and a gas discharge hole in the center portion. A separator plate having a circular shape with its outer peripheral edge joined to the outer peripheral edge of the cell plate, and a gas introduction located between each central portion of the cell plate and the separator plate and communicating with each gas introduction hole A plurality of solid electrolyte molds having a gas flow path communicating with the flow path and the gas discharge hole, and having a central flow path component for supplying and discharging fuel gas in a space formed between the cell plate and the separator plate The fuel cell units are stacked at the center of each, and the space between the solid oxide fuel cell units that overlap each other is set as an air flow path, and the gas introduction flow paths of the central flow path components are continuous with each other. Formation It is in the vicinity of the gas introduction passage to the upstream end, and characterized by providing the upstream end catalyst supporting density lower porous body in the vicinity.

  In the fuel cell stack structure of the present invention, the porous body is provided in the vicinity of the gas introduction passage formed by the gas introduction passages of the central flow passage component being continuous with each other or the upstream end thereof. If the area where the porous body is installed, that is, the portion where the heat capacity is supplied is heated by supplying a high-temperature fuel gas and the portion where the single cell is mounted is heated by heat transfer, the diameter is increased. The temperature distribution in the direction becomes uniform, and in addition, the heating time is shortened.

According to the present invention, the following effects can be obtained.
In addition to improving the efficiency of use of reforming heat and making the entire temperature distribution uniform, the start-up time can be shortened and a very compact effect can be achieved. It is.
Further, it is possible to prevent the reforming from occurring at a stretch in the vicinity of the upstream end portion of the gas introduction flow path and causing the temperature to rise locally.

  In the solid oxide fuel cell of the fuel cell stack structure according to the present invention, a plurality of solid electrolyte fuel cell units are stacked at the central portion of each, but there is a space between the overlapping solid oxide fuel cell units. Are formed as concentric with the outer peripheral edge of the solid oxide fuel cell unit cell plate and separator plate, and project in a direction away from each other. It is possible to adopt a configuration in which each of the convex stepped portions is formed, for example, formed by pressing, or a spacer is interposed between the central portions of the cell plate and the separator plate.

  In the solid oxide fuel cell of the fuel cell stack structure of the present invention, a porous body is installed in the vicinity of the gas introduction path formed by continuously connecting each gas introduction flow path of the central flow path component or the upstream end thereof. The center of the solid oxide fuel cell unit with a large heat capacity is heated by increasing the heat receiving area when the high temperature gas for heating is introduced. At this time, the porosity of the porous body May be changed in the stacking direction of the plurality of solid oxide fuel cell units.

  When the porous body is a metal, foam metal, mesh, felt, punching metal, or expanded metal can be used. On the other hand, when the porous body is ceramic, alumina or ceria is used. be able to.

  Further, in the solid oxide fuel cell of the fuel cell stack structure of the present invention, the gas introduction path formed by the gas introduction flow paths of the central flow path components being continuous with each other is the central axis of the solid oxide fuel cell unit. It is possible to adopt a configuration in which the gas discharge path formed by the gas discharge flow paths of the central flow path components being continuous with each other is positioned around the central axis of the solid oxide fuel cell unit. it can.

  However, the gas introduction path is not necessarily located on the central axis of the solid oxide fuel cell unit. For example, the gas formed by the gas discharge passages of the central passage component being continuous with each other. The discharge path is located on the central axis of the solid oxide fuel cell unit, and the gas introduction path formed by the gas flow paths of the central flow path components continuing to each other is the central axis of the solid oxide fuel cell unit. It is possible to have a configuration located around.

  As described above, when the gas introduction path is arranged around the central axis of the solid oxide fuel cell unit, the degree of freedom of the shape of the central portion of the solid oxide fuel cell unit is expanded and the gas introduction with the porous body is installed. Since the path is dispersed in the vicinity of the single cell, that is, the heat receiving portion and the heat generating portion is dispersed in the vicinity of the single cell, heat transfer is facilitated.

  When the gas introduction path is arranged around the central axis of the solid oxide fuel cell unit, it is symmetrical around the central axis in consideration of uniform heat distribution in the plane direction of the solid oxide fuel cell unit. It is desirable to arrange in.

  Furthermore, in the solid oxide fuel cell of the fuel cell stack structure according to the present invention, the porous body provided in the vicinity of the gas introduction path or its upstream end can carry the catalyst. That is, a porous body can be used as a reformer by supporting a metal such as Co, Ni, Ru, Rh, Pd, Ir, and Pt or an alloy containing these metals on the porous body as a catalyst. it can.

  At this time, the amount of the catalyst supported can be changed in either the stacking direction or the radial direction of the solid oxide fuel cell unit, and the vicinity of the upstream end of the gas introduction path, which is near the fuel gas inlet. When the catalyst support density is increased, reforming occurs at this point and the temperature rises locally. Therefore, it is desirable to reduce the catalyst support density in the vicinity of the upstream end of the gas introduction path.

  In this way, when the catalyst is supported on the porous body and the function of the reformer is incorporated inside, at the start-up, the central part of the stack structure is heated using the exothermic reaction at the time of partial oxidation reforming. Thus, the space can be saved by integrating the reformer, the heat insulating container can be simplified, and the thermal efficiency can be improved. In addition, during operation, the central portion of the stack structure can be cooled using the endothermic reaction during steam reforming, and abnormal temperature rise in the central portion of the stack structure can be suppressed.

  Furthermore, in the solid oxide fuel cell of the fuel cell stack structure of the present invention, it is possible to adopt a configuration in which the porous body is supported by the porous body supporting means inserted through the gas introduction path. As the porous body support means, for example, a fastening member of a stacked solid oxide fuel cell unit or a tubular member inserted into a gas introduction path can be adopted, but it is not limited to these members.

  Here, when the fastening member of the laminated solid oxide fuel cell unit is used as the porous body support means, and the porous body is filled around the fastening member and over the entire length of the gas introduction path, the solid oxide fuel cell is obtained. Although the gas concentration in the stacking direction of the units slightly changes, in addition to simplifying the structure, space saving is also achieved. At this time, if the porous body is arranged around the fastening member and at the upstream end of the gas introduction path, for example, a flange for pressing the stacked solid oxide fuel cell unit, only the periphery of the flange is heated. However, the concentration of the fuel gas distributed to each solid oxide fuel cell unit can be made uniform.

  On the other hand, when the tubular member inserted into the gas introduction path is used as the porous body support means and the porous body is accommodated in the hollow portion of the tubular member, the fuel gas supplied to the gas introduction path is once forcedly forced. After being sent to the downstream end, it is distributed to each solid oxide fuel cell unit, and therefore the uniformity of the fuel gas concentration is increased.

  At this time, the same effect as that in the case where the porous body is accommodated in the hollow portion of the tubular member can be obtained by adopting a configuration in which at least a part of the peripheral wall of the porous body located in the gas introduction path is a gas impermeable portion. Is obtained.

  In the case where the porous body is filled around the fastening member of the stacked solid oxide fuel cell unit and over the entire length of the gas introduction path, the porous wall is used as the porous body support means as the peripheral wall surface of the gas introduction path. The cylindrical porous body is brought into contact with the peripheral wall surface of the gas introduction path so that the fuel gas supplied to the gas introduction path flows outward from the hollow portion of the cylindrical porous body. In this case, since the movement distance (the thickness of the porous body) when the fuel gas passes through the porous body and flows into each solid oxide fuel cell unit is equal, The concentration can be made uniform.

  Furthermore, in the fuel cell stack structure of the present invention, a structure provided with a porous body support means such as a fastening member or a tubular member insulated from the solid oxide fuel cell unit or a heating mechanism for heating the porous body. In this case, since the catalyst can be heated by energizing the porous body support means or the porous body, the start-up time of the catalyst can be shortened, and as a result, the mobility is further improved. Will be improved.

  Furthermore, in the solid oxide fuel cell of the fuel cell stack structure according to the present invention, the porous body separately from the gas introduction flow path communicating with each gas introduction hole of the cell plate and the separator plate in the central flow path component. The reforming flow path is provided, and the upstream side of the reforming path formed by connecting the reforming paths of the central flow path components to each other is connected to the gas supply source and the most downstream of the reforming path Can be configured to be connected to a gas introduction path formed by the gas introduction flow paths being continuous with each other.

  In this case, the fuel gas supplied from the gas supply source is once sent to the most downstream side of the reforming path on which the porous body is installed, and then the gas introduction path that functions as a manifold connected to the most downstream side of the reforming path It will be distributed to each solid oxide fuel cell unit via the. That is, since all the fuel gas flows through the entire reforming path and is distributed to each solid oxide fuel cell unit, the uniformity of the fuel gas concentration is increased.

  Furthermore, in the solid oxide fuel cell of the fuel cell stack structure according to the present invention, a configuration may be provided in which a heating path for performing only heat exchange by flowing exhaust gas in the combustor or fuel gas via the heat exchanger is provided. Specifically, the heating flow for flowing the gas for heating the central portion of the solid oxide fuel cell unit to the central flow path component separately from the gas introduction flow paths communicating with the gas introduction holes of the cell plate and the separator plate, respectively. In order to form a heating path in the stacking direction passing through the central portion of the solid oxide fuel cell unit, it is possible to adopt a configuration in which the heating flow paths of the central flow path components are continuous with each other.

  A combustor or a heat exchanger can be used as a supply source of the gas for heating the central portion from the outside, but is not limited to these supply sources. Further, the position of a fastening member such as a bolt of the stacked solid oxide fuel cell unit is not particularly limited. It may be located on the central axis of the solid oxide fuel cell unit, around the central axis and outside the solid oxide fuel cell unit.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.

[Example 1]
1 to 5 show an embodiment of a fuel cell stack structure according to the present invention. As shown in FIGS. 1 and 2, the fuel cell stack structure 11 includes a plurality of solid oxide fuel cells. The units 1 are stacked in the same direction, and a plurality of stacked solid oxide fuel cell units 1 are sandwiched by flanges 13 and 14 from both sides (upper and lower sides in the drawing).

  As shown in FIG. 3, the solid oxide fuel cell unit 1 constituting the fuel cell stack structure 11 is formed of a metal having a circular thin plate shape and having a gas introduction hole 21 and a gas discharge hole 22 in the center. A cell plate 2 and a metal separator plate 3 having a circular thin plate shape and having a gas introduction hole 31 and a gas discharge hole 32 at the center are provided, and the cell plate 2 and the separator plate 3, the outer peripheral edges are joined to each other in a state of being opposed to each other, and the current collector 4 is accommodated in a bag portion (space) S formed between the cell plate 2 and the separator plate 3. is there.

  A circular convex step that is concentric with the outer peripheral edge and protrudes away from each other and functions as a spacer, as will be described later, at the center of each of the cell plate 2 and the separator plate 3 that are joined to face each other. The portions 23 and 33 are respectively formed by press working, and the outer peripheral edge portions of the cell plate 2 and the separator plate 3 are concentric with the outer peripheral edge portion and project in a direction approaching each other to form a space S. The annular steps 24 and 34 for forming are respectively formed by press working. The gas introduction holes 21 and 31 and the gas discharge holes 22 and 32 described above are arranged at the circular convex steps 23 and 33 of the cell plate 2 and the separator plate 3, respectively. A single cell 6 having a donut shape is fixed in the area between the two.

  Further, of the circular convex step portions 23 and 33 located at the central portions of the cell plate 2 and the separator plate 3, the circular convex step portion 33 of the separator plate 3 communicates with the gas introduction hole 31. A central flow path component 5 for supplying gas into the space S formed between the cell plate 2 and the separator plate 3 with the passage 51 is accommodated, and the circular convex step portion 23 of the cell plate 2 includes A central flow path component 5 that includes a gas discharge flow path 52 that communicates with the gas discharge hole 22 and discharges gas from the space S is accommodated. These central flow path components 5 and 5 will be described later. In addition, in the state where the stack structure 11 is formed by stacking the solid oxide fuel cell units 1, they are brought into close contact with each other only by the pressing force of the entire stack structure 11.

  Further, the fuel cell stack structure 11 in this embodiment is formed by laminating the above-described solid oxide fuel cell units 1 via a gas permeable current collector 15, and the solid oxide fuel cell units overlapping each other. Between 1 and 1 is set as an air flow path.

  Furthermore, in this fuel cell stack structure 11, the central holes formed at the centers of the cell plate 2 and the separator plate 3 serve as gas introduction holes 21, 31, and a plurality of holes formed around the central hole are gas. The gas introduction channels 51A are formed by connecting the gas introduction channels 51 of the central channel component 5 to each other through the gas introduction holes 21 and 31 to form the gas introduction channels 51A. The gas discharge passages 52A are formed by connecting the gas discharge passages 52 of the central flow passage component 5 to each other via 32.

  In this case, the gas introduction passage 51A formed by the gas introduction passages 51 of the central flow passage component 5 being continuous with each other includes metals such as Co, Ni, Ru, Rh, Pd, Ir, and Pt, and the like. A porous body 20 such as a foam metal or alumina carrying an alloy containing a metal as a catalyst is provided.

  In addition, between each center part of the solid oxide fuel cell unit 1 laminated | stacked mutually, the gas introduction holes 21 and 31 which mutually oppose, and several gas discharge holes 22 and 32 which mutually oppose are communicated in the airtight illustration There is no sealing material.

  And the solid oxide fuel cell unit 1 laminated | stacked through the said sealing material is fixed with the one volt | bolt 16, In this Example, as shown also in FIG.4 and FIG.5, as shown in FIG. Bolts 16 penetrating the flange 13 through the insulating washer 17 are inserted into the gas introduction passages 51A formed by the gas introduction passages 51 of the flow passage component 5 being continuous with each other, and are externally connected from the flange 14 to the outside. A plurality of solid oxide fuel cell units 1 are fastened by screwing nuts 19 into the front end portions of the bolts 16 protruding inward via insulating washers 17 and disc springs 18.

  At this time, the porous body 20 installed in the gas introduction path 51A is in a state of being filled around the bolt 16 as a fastening member and over the entire length of the gas introduction path 51A. In addition, the code | symbol T of FIG. 2 is an output terminal.

  In this example, the cell plate 2 and the separator plate 3 were SUS430 rolled plates having a thickness of 0.1 mm. Then, this rolled plate was set in a press machine equipped with a die made of cemented carbide and SKD11 and subjected to press working with a press load of 80 tons. The outer diameter of the cell plate 2 and the separator plate 3 obtained by this pressing is 125 mm, the step size is 1 mm for both the circular convex steps 23 and 33 and the annular steps 24 and 34, and the outer peripheral edges of both separators 2 and 3. Laser welding was used for joining the parts.

  On the other hand, SUS430 is also used for the central flow path component 5, and the cell plate 2 and the separator plate 3 are fixed by diffusion bonding in a vacuum at a bonding temperature of 1000 ° C. or less to prevent deformation at the time of bonding. Yes. In addition, instead of diffusion bonding, bonding by laser welding using a YAG laser is also possible. At this time, since the cell plate 2 and the separator plate 3 are in a thin plate shape, even if laser is irradiated from the front side Can be joined. In addition, the flow path pattern of the central flow path component 5 can be formed by etching, grinding, or laser processing, and can also be formed by stacking and joining etched components.

  In the stack structure 11, air flows between the solid oxide fuel cell unit 1 and the solid oxide fuel cell unit 1 laminated thereon, that is, the current collector 15 disposed between the layers on the cathode side. On the other hand, as shown in FIGS. 2 and 4, the fuel gas passes between the cell plate 2 and the separator plate 3 through the flange 13, the gas introduction path 51 </ b> A of the solid oxide fuel cell unit 1, and the gas introduction holes 21 and 31. After being introduced into each space S to be formed and flowing through the space S, the gas is exhausted through the gas discharge path 52 </ b> A and the flange 14.

  In the fuel cell stack structure 11 described above, since the porous body 20 is provided in the gas introduction passage 51A formed by the gas introduction passages 51 of the central passage component 5 being continuous with each other, the heat receiving area is increased. That is, if the gas introduction path 51A in which the porous body 20 is installed, that is, a portion having a large heat capacity is heated by supplying a high-temperature fuel gas and the portion on which the single cell 6 is mounted by heat transfer, The temperature distribution in the direction becomes uniform, and in addition, the heating time is shortened.

  Further, in the fuel cell stack structure 11 described above, the porous body 20 is filled around the bolt 16 as a fastening member and over the entire length of the gas introduction path 51A, so the stacking direction of the solid oxide fuel cell unit 1 is increased. Although the gas concentration slightly changes, in addition to the simplification of the structure, space saving is also achieved.

  As shown in FIG. 6, the porous body 20 may be disposed around the bolt 16 and at the upstream end of the gas introduction path 51A, for example, the flange 13, and in this case, the flange 13 Although only the periphery may be heated, the concentration of the fuel gas distributed to each solid oxide fuel cell unit 1 is made uniform.

  In the above-described embodiment, the case where the single cell 6 has a donut shape is shown. However, the present invention is not limited to this. For example, as shown in FIG. 7, the single cell 6A has a small-diameter disk shape. In this case, it is preferable to arrange the plurality of single cells 6A at equal intervals in the region between the inner peripheral edge and the outer peripheral edge of the cell plate 2.

[Example 2]
8 and 9 show another embodiment of the fuel cell stack structure of the present invention. As shown in FIGS. 8 and 9, in the fuel cell stack structure 11 of this embodiment, the tubular member 46 disposed coaxially with the bolt 16 in the gas introduction path 5A is used as the porous body support means, and the porous body 20 is used. Is filled in the hollow portion of the tubular member 46 and over the entire length of the gas introduction path 51A, that is, the porous body 20 is filled between the bolt 16 and the tubular member 46 and over the entire length of the gas introduction path 51A.

  In the fuel cell stack structure 11 of this embodiment, the fuel gas supplied to the gas introduction path 51A is once forcibly sent to the downstream end and then the solid oxide fuel through the gas introduction holes 21 and 31. Therefore, the fuel gas concentration is more uniform.

  At this time, the tubular member 46 as the porous body support means is not disposed, and at least a part of the peripheral wall of the porous body 20 supported by the bolt 16 in the gas introduction path 51A is formed as a gas impermeable portion. Also by this, the same effect as the case where the porous body 20 is accommodated in the hollow portion of the tubular member 46 can be obtained.

[Example 3]
FIG. 10 shows still another embodiment of the fuel cell stack structure of the present invention. As shown in FIG. 10, in the fuel cell stack structure 11 of this embodiment, the peripheral wall surface 51a of the gas introduction path 51A is used as a porous body support means, and the porous body 20 is formed in a cylindrical shape. The porous body 20 is brought into contact with the peripheral wall surface 51a of the gas introduction path 51A so that the fuel gas supplied to the gas introduction path 51A flows from the hollow portion of the cylindrical porous body 20 to the outside.

  In the fuel cell stack structure 11 of this embodiment, the movement distance (the thickness of the porous body 20) when the fuel gas passes through the porous body 20 and flows into each solid oxide fuel cell unit 1 is the same. Therefore, the fuel gas concentration can be made uniform.

[Example 4]
FIG. 11 shows still another embodiment of the fuel cell stack structure of the present invention. As shown in FIG. 11, in the fuel cell stack structure 11 of this embodiment, the gas introduction passage 51A formed by connecting the gas introduction passages 51 of the central passage component 5 to each other, and the central passage component 5 In addition to the gas discharge passage 51B formed by connecting the gas discharge passages 52 to each other, a plurality of bolt insertion holes 53 are provided around the gas introduction passage 51A, and the stacked solid oxide fuel cell units 1 are The plurality of bolts 16 respectively inserted into the bolt insertion holes 53 are fastened and fixed, and the porous body 20 is filled with almost no gap over the entire length of the gas introduction path 51A.

  In this embodiment, in addition to the same effects as the fuel cell stack structure 11 described above, the stacked solid oxide fuel cell unit 1 can be fastened and fixed with a plurality of bolts 16. 16 can be prevented from being deformed by thermal stress.

  In this embodiment, the case where the porous body 20 is filled with almost no gap over the entire length of the gas introduction path 51A is shown. However, as another arrangement example, for example, as shown in FIG. The body 20 is disposed on the central axis of the solid oxide fuel cell unit 1 with a gap from the peripheral wall 51a of the gas introduction path 51A, or a porous body formed in a cylindrical shape as shown in FIG. The body 20 can be arranged in a state in which the body 20 is in contact with the peripheral wall surface 51a of the gas introduction path 51A.

[Example 5]
13 and 14 show still another embodiment of the fuel cell stack structure of the present invention. As shown in FIGS. 13 and 14, in the fuel cell stack structure 11 of this embodiment, the center holes formed at the centers of the cell plate 2 and the separator plate 3 are the gas discharge holes 22 and 32, and the center holes A plurality of holes formed around the gas inlet holes 21 and 31 are used. That is, the gas discharge passages 52 </ b> A formed by connecting the gas discharge passages 52 of the central flow passage component 5 to each other through the gas discharge holes 22 and 32 are positioned at the centers of the cell plate 2 and the separator plate 3. The gas introduction passage 51A formed by connecting the gas introduction passages 51 of the central passage component 5 to each other through the gas introduction holes 21 and 31 is positioned around the gas discharge passage 52A.

  In the fuel cell stack structure 11, a plurality of reforming channels 54 for arranging the porous body 20 are arranged around the gas discharge channel 52 </ b> A in the central channel component 5, separately from the gas introduction channel 51. The upstream side of the plurality of reforming paths 54A formed by the reforming channels 54 of the central channel part 5 being continuous with each other is connected to the gas supply source, and the most downstream of the reforming path 54A is connected to each gas. Each of the introduction flow paths 51 is connected to a gas introduction path 51A formed by being continuous with each other, and the bolt 16 penetrating the flange 13 through the insulating washer 17 is inserted into the gas discharge path 52A. A plurality of solid oxide fuel cell units 1 are fastened by screwing nuts 19 through insulating washers 17 and disc springs 18 to the front ends of bolts 16 projecting outward from the flange 14. .

  In the fuel cell stack structure 11 according to this embodiment, the fuel gas supplied from the gas supply source is once sent to the most downstream sides of the plurality of reforming paths 54A in which the porous body 20 is installed, and then these modifications are made. The gas is distributed to each solid oxide fuel cell unit 1 through a gas introduction path 51A that functions as a manifold connected to the most downstream side of the mass path 54A. That is, since all the fuel gas flows through the entire reforming path 54A and then is distributed to each solid oxide fuel cell unit 1, the uniformity of the fuel gas concentration is increased.

[Example 6]
15 and 16 show still another embodiment of the fuel cell stack structure of the present invention. As shown in FIG. 15, in the fuel cell stack structure 11 of this embodiment, a plurality of stacked solid oxide fuel cell units 1 are sandwiched from both sides (upper and lower sides in the drawing) by rectangular flanges 13A and 14A. As shown in FIG. 16, the porous body 20 has almost no gap over the entire length of the gas introduction path 51A. Filled.

  In this embodiment, in addition to the same effects as the fuel cell stack structure 11 described above, the stacked solid oxide fuel cell units 1 are fastened with four bolts 16 positioned around them. Since it can fix, the deformation | transformation by the thermal stress concerning the volt | bolt 16 can be prevented.

  In this embodiment, the case where the porous body 20 is filled with almost no gap over the entire length of the gas introduction path 51A is shown. However, as another arrangement example, for example, as shown in FIG. It can be disposed on the central axis of the solid oxide fuel cell unit 1 with a gap from the peripheral wall 51a of the gas introduction path 51A.

[Example 7]
FIG. 18 shows still another embodiment of the fuel cell stack structure of the present invention. As shown in FIG. 18, in the fuel cell stack structure 11 of this embodiment, in the fuel cell stack structure 11 in the above-described embodiment 5, that is, a plurality of gas pipes 51 </ b> A connected to the gas introduction paths 51 </ b> A. In the fuel cell stack structure 11 having the reforming path 54A, a plurality of stacked solid oxide fuel cell units 1 are sandwiched from both sides (upper and lower sides in the drawing) by rectangular flanges 13A and 14A, and these flanges 13A and 14A are sandwiched between them. The four bolts 16 spanning the four corners are fastened and fixed.

  In the fuel cell stack structure 11 of this embodiment, in addition to the same effects as the fuel cell stack structure 11 in the embodiment 5, the stacked solid oxide fuel cell units 1 are positioned around these. Since the four bolts 16 can be fastened and fixed, deformation due to thermal stress applied to the bolts 16 can be prevented.

  In the fuel cell stack structure 11 of Examples 1 to 7 described above, the porous body supporting means such as the bolt 16 and the tubular member 46 or the porous body 20 as fastening members insulated from the solid oxide fuel cell unit 1. A structure provided with a heating mechanism (not shown) for heating itself can be employed. In this case, the catalyst is provided by energizing the porous body supporting means such as the bolt 16 and the tubular member 46 or the porous body 20 itself. Since the catalyst can be heated, the starting time of the catalyst can be shortened, and as a result, the mobility can be further improved.

[Example 8]
FIG. 19 shows still another embodiment of the fuel cell stack structure of the present invention. In the fuel cell stack structure 11 of this embodiment, as shown in FIG. 19, a gas introduction channel 51 that communicates with the gas introduction holes 21 and 31 of the cell plate 2 and the separator plate 3 in the central channel component 5. Separately, a heating channel 55 for flowing a gas for heating the central portion of the solid oxide fuel cell unit 1 is provided, and a central heating channel 55A passing through the central portion of the solid oxide fuel cell unit 1 is formed in the center. Each heating channel 51 of the channel component 5 is configured to be continuous with each other. Also in this case, since the catalyst can be heated by flowing the heating gas through the heating path 55A, the start-up time of the catalyst can be shortened, and as a result, the mobility is further improved.

  A combustor or a heat exchanger can be used as a supply source of the gas for heating the central portion from the outside, but is not limited to these supply sources.

It is a disassembled perspective explanatory drawing which shows one Example of the fuel cell stack structure of this invention. Example 1 FIG. 2 is a cross-sectional explanatory view of the fuel cell stack structure in FIG. 1 based on the position of FIG. 1A-B line. Example 1 FIG. 2 is an exploded perspective view of a solid oxide fuel cell unit constituting the fuel cell stack structure in FIG. 1. Example 1 FIG. 2 is a partially enlarged cross-sectional explanatory view of the fuel cell stack structure in FIG. 1 based on the position of FIG. 1A-B line. Example 1 FIG. 2 is an explanatory plan view of a central flow path component showing a positional relationship among a gas introduction path, a gas discharge path, and a porous body of the fuel cell stack structure in FIG. 1. Example 1 FIG. 7 is a partially enlarged cross-sectional explanatory view at a position corresponding to the line of FIGS. 1A and 1B showing another arrangement example of the porous body in the fuel cell stack structure of FIG. 1. FIG. 3 is an exploded perspective view showing another configuration example of the solid oxide fuel cell unit constituting the fuel cell stack structure in FIG. 1. FIG. 7 is a partially enlarged cross-sectional explanatory view at a position corresponding to the line of FIGS. (Example 2) FIG. 9 is an explanatory plan view of a central flow path component showing a positional relationship among a gas introduction path, a gas discharge path, and a porous body of the fuel cell stack structure in FIG. 8. (Example 2) FIG. 6 is an explanatory plan view of a central flow path component showing a positional relationship among a gas introduction path, a gas discharge path, and a porous body of a fuel cell stack structure according to still another embodiment of the present invention. (Example 3) FIG. 6 is an explanatory plan view of a central flow path component showing a positional relationship among a gas introduction path, a gas discharge path, and a porous body of a fuel cell stack structure according to still another embodiment of the present invention. Example 4 It is plane explanatory drawing (a), (b) of center flow path components which shows the other arrangement pattern of the gas introduction path of the fuel cell stack structure in FIG. 11, a gas exhaust path, and a porous body. FIG. 7 is a partially enlarged cross-sectional explanatory view at a position corresponding to FIG. 1A-B showing still another embodiment of the fuel cell stack structure of the present invention. (Example 5) FIG. 14 is an explanatory plan view of a central flow path component showing a positional relationship among a gas introduction path, a gas discharge path, and a porous body of the fuel cell stack structure in FIG. 13. (Example 5) It is a disassembled perspective explanatory drawing which shows the further another Example of the fuel cell stack structure of this invention. (Example 6) FIG. 16 is an explanatory plan view of a central flow path component showing a positional relationship among a gas introduction path, a gas discharge path, and a porous body of the fuel cell stack structure in FIG. 15. (Example 6) FIG. 16 is an explanatory plan view of a central flow path component showing another arrangement example of the porous body in the fuel cell stack structure of FIG. 15. FIG. 5 is a partial plan view showing still another embodiment of the fuel cell stack structure according to the present invention. (Example 7) FIG. 6 is an explanatory plan view of a central flow path component showing a positional relationship among a gas introduction path, a gas discharge path, and a porous body of a fuel cell stack structure according to still another embodiment of the present invention. (Example 8)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell unit 2 Cell plate 3 Separator plate 5 Central flow path component 6 Single cell 11 Stack structure 16 Bolt (fastening member; porous body support means)
20 Porous body 21, 31 Gas introduction hole 22, 32 Gas discharge hole 46 Tubular member (porous body support means)
51 Gas Introducing Channel 51A Gas Introducing Channel 52 Gas Discharging Channel 52A Gas Discharging Channel 54 Reforming Channel 54A Reforming Channel 55 Heating Channel 55A Heating Channel S Space

Claims (11)

A cell plate that holds a single cell and has a circular shape having a gas introduction hole and a gas discharge hole in the center portion;
A separator plate having a circular shape in which a gas introduction hole and a gas discharge hole are formed in the center portion and an outer peripheral edge portion thereof is joined to an outer peripheral edge portion of the cell plate;
A gas introduction passage located between the central portions of the cell plate and the separator plate and communicating with each gas introduction hole and a gas discharge passage communicating with the gas discharge hole are formed between the cell plate and the separator plate. A plurality of solid oxide fuel cell units each provided with a central flow path component for supplying and discharging fuel gas in a space to be stacked at each central portion;
The space between the solid oxide fuel cell units that overlap each other is set as an air flow path, and the gas introduction flow path formed by the gas flow paths of the central flow path component being continuous with each other or in the vicinity of the upstream end thereof. A fuel cell stack structure characterized in that a porous body having a reduced catalyst carrying density in the vicinity of its upstream end is provided.   The gas introduction passage formed by the gas introduction passages of the central passage component being continuous with each other is located on the central axis of the solid oxide fuel cell unit, and the gas discharge passages of the central passage component are continuous with each other. 2. The fuel cell stack structure according to claim 1, wherein the gas discharge path formed as a result is located around the central axis of the solid oxide fuel cell unit.   The gas discharge passage formed by the gas discharge passages of the central flow passage component being continuous with each other is located on the central axis of the solid oxide fuel cell unit, and the gas introduction passages of the central flow passage component are continuous with each other. 2. The fuel cell stack structure according to claim 1, wherein the gas introduction path formed is positioned around a central axis of the solid oxide fuel cell unit. The fuel cell stack structure according to any one of claims 1 to 3 , wherein the porous body is supported by a porous body support means inserted through the gas introduction path . The fastening member of the laminated solid oxide fuel cell unit is used as a porous body support means, and the porous body
The fuel cell stack structure according to claim 4 , wherein the fuel cell stack structure is disposed around the fastening member . A tubular member inserted into the gas introduction path is used as a porous body support means, and the porous body is a hollow portion of the tubular member.
6. The fuel cell stack structure according to claim 5, wherein the fuel cell stack structure is contained in a minute . Original claim 8
The fuel cell stack structure according to any one of claims 1 to 6, wherein at least a part of the peripheral wall of the porous body located in the gas introduction path is a gas impermeable portion .   The fuel cell stack structure according to any one of claims 5 to 8, further comprising a porous body support means insulated from the solid oxide fuel cell unit or a heating mechanism for heating the porous body. In addition to the gas introduction channels communicating with the gas introduction holes of the cell plate and the separator plate, the central channel component is provided with a reforming channel for arranging the porous body, and each reforming flow of the central channel component is provided. The upstream side of the reforming path formed by the continuous paths is connected to the gas supply source, and the most downstream side of the reforming path is connected to the gas introducing path formed by the continuous gas introducing channels The fuel cell stack structure according to claim 3 to be connected . In addition to the gas introduction flow paths communicating with the gas introduction holes of the cell plate and the separator plate, the central flow path component is provided with a heating flow path for flowing a gas for heating the central portion of the solid oxide fuel cell unit. The fuel cell stack according to any one of claims 1 to 9 , wherein each heating flow path of the central flow path component is made continuous with each other so as to form a heating path in the stacking direction that penetrates the central portion of the fuel cell unit. Structure. A cell plate that holds a single cell and has a circular shape having a gas introduction hole and a gas discharge hole in the center portion;
A separator plate having a circular shape in which a gas introduction hole and a gas discharge hole are formed in the center portion and an outer peripheral edge portion thereof is joined to an outer peripheral edge portion of the cell plate;
A gas introduction passage located between the central portions of the cell plate and the separator plate and communicating with each gas introduction hole and a gas discharge passage communicating with the gas discharge hole are formed between the cell plate and the separator plate. A plurality of solid oxide fuel cell units each provided with a central flow path component for supplying and discharging fuel gas in a space to be stacked at each central portion;
The space between the solid oxide fuel cell units that overlap each other is set as an air flow path, and the gas introduction flow path formed by the gas flow paths of the central flow path component being continuous with each other or in the vicinity of the upstream end thereof. Providing a porous body,
The porous body is supported by the porous body support means inserted through the gas introduction path,
A fuel cell stack structure characterized in that the fastening member of the laminated solid oxide fuel cell unit is a porous body supporting means, and the porous body is disposed around the fastening member .

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